Variation in root morphology of epiphytic orchids along small-scale and large-scale moisture gradients
Variation in root morphology of epiphytic orchids along small-scale and large-scale moisture gradients
复制标题
DOI：
10.1590/0102-33062019abb0198
复制
发表时间：
2020-03-01
影响因子：
1.1
通讯作者：
Zotz, Gerhard
中科院分区：
文献类型：
--
作者：
Einzmann, Helena J. R.;Schickenberg, Nina;Zotz, Gerhard
根的形态预计会对环境条件作出反应。两个较早的研究报告可预测的变化，根膜的结构（常见的单子叶植物）沿着降雨梯度，这是预期从其假定的作用，在植物水的关系。本研究扩展了这一想法，通过分析9根性状，可以链接到根功能，包括根膜结构，沿着两个不同的空间尺度的水分梯度：1）沿着在巴拿马中部和2）沿着一个强大的区域降雨梯度在巴拿马西部的低地森林的垂直梯度。所有研究的45种兰花的性状（如被膜宽度，木质部极数，木质化的外皮）表现出实质性的种内和种间变异，但没有这在森林内）或很少这（区域梯度）是梯度相关。只有根被宽度、中柱宽度和木质部极数的群落加权平均值随降雨量的变化达到显著水平，后两个性状的显著效应量。我们的结果显然不同意那些早期的出版物，其中没有包括物种丰富度和/或严格的统计数据在他们的分析。这种差异突出表明，我们对膜的形式和功能之间的联系的理解仍然是初步的。
Root morphology is expected to respond to environmental conditions. Two earlier studies reported predictable changes in the structure of the velamen radicum (common in monocotyledons) along rainfall gradients, which was expected from its assumed role in plant-water-relations. The present study expanded on this idea by analysing nine root traits that can be linked to root function, including velamen structure, along two moisture gradients of different spatial scales: 1) along the vertical gradient of a lowland forest in central Panama and 2) along a strong regional rainfall gradient in western Panama. All studied traits (e.g. velamen width, number of xylem poles, lignification of the exodermis) of the 45 orchid species showed substantial intraspecific and interspecific variation, but none of this within forest) or very little of this (regional gradient) was related to the gradients. Only the community weighted means of velamen width, stele width and xylem pole number varied significantly with rainfall, with substantial effect sizes only found in the latter two traits. Our results clearly disagree with those of earlier publications, which did not include species abundance and/or rigorous statistics in their analyses. This discrepancy highlights that our understanding of the link between velamen form and function is still rudimentary.